Influence of Heating Temperature and Holding Time on the Grain Size of Resistance Wires

For investigating the impact of heating temperature and holding time on crystal grain size of FeCrAl resistance wires, the resistance wires were heated by Muffle furnace. And the image analysis software was used to measure the mean sectional area of crystal grains on different heating conditions. The results show that the crystal grains of resistance wires grew in varying degrees with different heating temperature and holding time, and the growth degree of grains was obvious when the temperature reached at 800 ℃. The quantitative metallographic analysis on the grain size of resistance wires could provide some certain references for the identification of fire evidences.